1. Field of the Invention
This invention relates to exercise treadmills and more particularly to a treadmill which changes slope and height during exercising.
2. Description of the Related Art
Walking is a very good form of exercise. It has a low impact on the body and yet increases the heart rate and expends energy to burn calories.
In the past treadmills for exercising were either flat to simulate walking on a flat surface or inclined to provide an upward slope to simulate an uphill walk designed to expend more energy than walking on a flat surface. However since the average center of gravity change of the person exercising on the upward slope treadmill is zero the exerciser on average does no work to lift his body and thus does not expend much more energy than walking on a flat surface treadmill.
Other exercise devices use a stair climbing simulation where the person has to bend his knees to expend energy to lift his body using muscles related to the bending of the knee to raise himself. This is more tiring and stressful on the body than a walking uphill on a small slope where the leg is kept essentially straight.